In the related art, as a power conversion device that converts AC power source into DC power and supplies the DC power to a load, a power conversion device is known, for example, which includes a rectifier that full-wave rectifies an input from an AC power source and a chopper circuit having a switching element of which ON and OFF states are switched in response to a PWM signal. In the chopper circuit of the power conversion device, a current waveform is rectified to improve a power factor and to reduce harmonics of an input current by short-circuiting the power source via a reactor by ON-OFF control of the switching element, and an output voltage is stepped up and down by charging and discharging the reactor with energy.
In such a power conversion device, a frequency at which the switching element is turned on and off is in inverse proportion to an inductance value of the reactor. Accordingly, a technique for reducing the inductance value of the reactor at the time of high-frequency switching has been proposed. For example, Patent Literature 1 discloses a “power supply device including first and second input terminals which are supplied with an input voltage, first and second output terminals from which an output voltage is taken, a choke coil of which one end is connected to the first input terminal and the other end is connected to the first output terminal via a diode, a switching element which is connected between a connection point between the other end of the choke coil and the diode and the second output terminal, a capacitor which is connected between a connection point between the diode and the first output terminal and the second output terminal, a comparator that compares a current flowing when the switching element is turned on with a predetermined threshold value, an oscillator, a pulse-width modulation circuit that controls a duty ratio of a pulse signal formed from an output signal of the oscillator so as to stabilize the output voltage, a frequency switching circuit that is supplied with an output signal from the pulse-width modulation circuit and switches the frequency of the output signal based on a comparison signal from the comparator, and a PFC control circuit that causes the frequency switching circuit to output a pulse signal for turning on and off the switching element therefrom, in which the frequency switching circuit switches the frequency of the pulse signal to a higher frequency when the current flowing when the switching element is turned on is greater than the threshold value or equal to or greater than the threshold value”.